Stabilizing and Activating Active Sites: 1T-MoS₂ Supported Pd Single Atoms for Efficient Hydrogen Evolution Reaction

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Metallic 1T-MoS2 exhibits high electronic conductivity and platinum-like catalytic activity for the hydrogen evolution reaction (HER).
• Synthesizing pure 1T-MoS2 is difficult due to its high formation energy and metastable nature.

Purpose of the Study:

• To develop a stable and highly active catalyst for the hydrogen evolution reaction (HER).
• To synthesize a thin layer of 1T-MoS2 on carbon support and immobilize single palladium atoms for enhanced catalytic properties.

Main Methods:

• In situ SO4(2-)-anchoring strategy to synthesize 1T-MoS2 on commercial carbon.
• Immobilization of single palladium atoms onto the 1T-MoS2 surface via Pd-S bonds.
• Electrochemical characterization (overpotential, Tafel slope, charge transfer resistance) in alkaline, acid, and neutral electrolytes.
• Atomic structural characterization and theoretical calculations.

Main Results:

• The Pd1/1T-MoS2/C catalyst demonstrated superior HER performance with a low overpotential (53 mV at 10 mA cm-2) and a small Tafel slope (37 mV dec-1).
• The catalyst exhibited excellent stability and activity across alkaline, acid, and neutral electrolytes.
• Theoretical calculations indicated that the high activity stems from near-zero hydrogen adsorption energy at activated sulfur sites adjacent to atomic palladium.

Conclusions:

• The in situ SO4(2-)-anchoring strategy effectively synthesizes a stable 1T-MoS2 support for single-atom palladium catalysts.
• The Pd1/1T-MoS2/C catalyst represents a highly efficient and versatile electrocatalyst for the hydrogen evolution reaction.
• The study highlights the potential of single-atom catalysts on 2D materials for advanced energy applications.